arch/s390/mm/cmm.c

   1 /*
   2  *  Collaborative memory management interface.
   3  *
   4  *    Copyright IBM Corp 2003,2010
   5  *    Author(s): Martin Schwidefsky <schwidefsky@de.ibm.com>,
   6  *
   7  */
   8
   9 #include <linux/errno.h>
  10 #include <linux/fs.h>
  11 #include <linux/init.h>
  12 #include <linux/module.h>
  13 #include <linux/gfp.h>
  14 #include <linux/sched.h>
  15 #include <linux/sysctl.h>
  16 #include <linux/ctype.h>
  17 #include <linux/swap.h>
  18 #include <linux/kthread.h>
  19 #include <linux/oom.h>
  20 #include <linux/suspend.h>
  21 #include <linux/uaccess.h>
  22
  23 #include <asm/pgalloc.h>
  24 #include <asm/diag.h>
  25
  26 static char *sender = "VMRMSVM";
  27 module_param(sender, charp, 0400);
  28 MODULE_PARM_DESC(sender,
  29                  "Guest name that may send SMSG messages (default VMRMSVM)");
  30
  31 #include "../../../drivers/s390/net/smsgiucv.h"
  32
  33 #define CMM_NR_PAGES ((PAGE_SIZE / sizeof(unsigned long)) - 2)
  34
  35 struct cmm_page_array {
  36         struct cmm_page_array *next;
  37         unsigned long index;
  38         unsigned long pages[CMM_NR_PAGES];
  39 };
  40
  41 static long cmm_pages;
  42 static long cmm_timed_pages;
  43 static volatile long cmm_pages_target;
  44 static volatile long cmm_timed_pages_target;
  45 static long cmm_timeout_pages;
  46 static long cmm_timeout_seconds;
  47 static int cmm_suspended;
  48
  49 static struct cmm_page_array *cmm_page_list;
  50 static struct cmm_page_array *cmm_timed_page_list;
  51 static DEFINE_SPINLOCK(cmm_lock);
  52
  53 static struct task_struct *cmm_thread_ptr;
  54 static DECLARE_WAIT_QUEUE_HEAD(cmm_thread_wait);
  55 static DEFINE_TIMER(cmm_timer, NULL, 0, 0);
  56
  57 static void cmm_timer_fn(unsigned long);
  58 static void cmm_set_timer(void);
  59
  60 static long cmm_alloc_pages(long nr, long *counter,
  61                             struct cmm_page_array **list)
  62 {
  63         struct cmm_page_array *pa, *npa;
  64         unsigned long addr;
  65
  66         while (nr) {
  67                 addr = __get_free_page(GFP_NOIO);
  68                 if (!addr)
  69                         break;
  70                 spin_lock(&cmm_lock);
  71                 pa = *list;
  72                 if (!pa || pa->index >= CMM_NR_PAGES) {
  73                         /* Need a new page for the page list. */
  74                         spin_unlock(&cmm_lock);
  75                         npa = (struct cmm_page_array *)
  76                                 __get_free_page(GFP_NOIO);
  77                         if (!npa) {
  78                                 free_page(addr);
  79                                 break;
  80                         }
  81                         spin_lock(&cmm_lock);
  82                         pa = *list;
  83                         if (!pa || pa->index >= CMM_NR_PAGES) {
  84                                 npa->next = pa;
  85                                 npa->index = 0;
  86                                 pa = npa;
  87                                 *list = pa;
  88                         } else
  89                                 free_page((unsigned long) npa);
  90                 }
  91                 diag10(addr);
  92                 pa->pages[pa->index++] = addr;
  93                 (*counter)++;
  94                 spin_unlock(&cmm_lock);
  95                 nr--;
  96         }
  97         return nr;
  98 }
  99
 100 static long cmm_free_pages(long nr, long *counter, struct cmm_page_array **list)
 101 {
 102         struct cmm_page_array *pa;
 103         unsigned long addr;
 104
 105         spin_lock(&cmm_lock);
 106         pa = *list;
 107         while (nr) {
 108                 if (!pa || pa->index <= 0)
 109                         break;
 110                 addr = pa->pages[--pa->index];
 111                 if (pa->index == 0) {
 112                         pa = pa->next;
 113                         free_page((unsigned long) *list);
 114                         *list = pa;
 115                 }
 116                 free_page(addr);
 117                 (*counter)--;
 118                 nr--;
 119         }
 120         spin_unlock(&cmm_lock);
 121         return nr;
 122 }
 123
 124 static int cmm_oom_notify(struct notifier_block *self,
 125                           unsigned long dummy, void *parm)
 126 {
 127         unsigned long *freed = parm;
 128         long nr = 256;
 129
 130         nr = cmm_free_pages(nr, &cmm_timed_pages, &cmm_timed_page_list);
 131         if (nr > 0)
 132                 nr = cmm_free_pages(nr, &cmm_pages, &cmm_page_list);
 133         cmm_pages_target = cmm_pages;
 134         cmm_timed_pages_target = cmm_timed_pages;
 135         *freed += 256 - nr;
 136         return NOTIFY_OK;
 137 }
 138
 139 static struct notifier_block cmm_oom_nb = {
 140         .notifier_call = cmm_oom_notify,
 141 };
 142
 143 static int cmm_thread(void *dummy)
 144 {
 145         int rc;
 146
 147         while (1) {
 148                 rc = wait_event_interruptible(cmm_thread_wait,
 149                         (!cmm_suspended && (cmm_pages != cmm_pages_target ||
 150                          cmm_timed_pages != cmm_timed_pages_target)) ||
 151                          kthread_should_stop());
 152                 if (kthread_should_stop() || rc == -ERESTARTSYS) {
 153                         cmm_pages_target = cmm_pages;
 154                         cmm_timed_pages_target = cmm_timed_pages;
 155                         break;
 156                 }
 157                 if (cmm_pages_target > cmm_pages) {
 158                         if (cmm_alloc_pages(1, &cmm_pages, &cmm_page_list))
 159                                 cmm_pages_target = cmm_pages;
 160                 } else if (cmm_pages_target < cmm_pages) {
 161                         cmm_free_pages(1, &cmm_pages, &cmm_page_list);
 162                 }
 163                 if (cmm_timed_pages_target > cmm_timed_pages) {
 164                         if (cmm_alloc_pages(1, &cmm_timed_pages,
 165                                            &cmm_timed_page_list))
 166                                 cmm_timed_pages_target = cmm_timed_pages;
 167                 } else if (cmm_timed_pages_target < cmm_timed_pages) {
 168                         cmm_free_pages(1, &cmm_timed_pages,
 169                                        &cmm_timed_page_list);
 170                 }
 171                 if (cmm_timed_pages > 0 && !timer_pending(&cmm_timer))
 172                         cmm_set_timer();
 173         }
 174         return 0;
 175 }
 176
 177 static void cmm_kick_thread(void)
 178 {
 179         wake_up(&cmm_thread_wait);
 180 }
 181
 182 static void cmm_set_timer(void)
 183 {
 184         if (cmm_timed_pages_target <= 0 || cmm_timeout_seconds <= 0) {
 185                 if (timer_pending(&cmm_timer))
 186                         del_timer(&cmm_timer);
 187                 return;
 188         }
 189         if (timer_pending(&cmm_timer)) {
 190                 if (mod_timer(&cmm_timer, jiffies + cmm_timeout_seconds*HZ))
 191                         return;
 192         }
 193         cmm_timer.function = cmm_timer_fn;
 194         cmm_timer.data = 0;
 195         cmm_timer.expires = jiffies + cmm_timeout_seconds*HZ;
 196         add_timer(&cmm_timer);
 197 }
 198
 199 static void cmm_timer_fn(unsigned long ignored)
 200 {
 201         long nr;
 202
 203         nr = cmm_timed_pages_target - cmm_timeout_pages;
 204         if (nr < 0)
 205                 cmm_timed_pages_target = 0;
 206         else
 207                 cmm_timed_pages_target = nr;
 208         cmm_kick_thread();
 209         cmm_set_timer();
 210 }
 211
 212 static void cmm_set_pages(long nr)
 213 {
 214         cmm_pages_target = nr;
 215         cmm_kick_thread();
 216 }
 217
 218 static long cmm_get_pages(void)
 219 {
 220         return cmm_pages;
 221 }
 222
 223 static void cmm_add_timed_pages(long nr)
 224 {
 225         cmm_timed_pages_target += nr;
 226         cmm_kick_thread();
 227 }
 228
 229 static long cmm_get_timed_pages(void)
 230 {
 231         return cmm_timed_pages;
 232 }
 233
 234 static void cmm_set_timeout(long nr, long seconds)
 235 {
 236         cmm_timeout_pages = nr;
 237         cmm_timeout_seconds = seconds;
 238         cmm_set_timer();
 239 }
 240
 241 static int cmm_skip_blanks(char *cp, char **endp)
 242 {
 243         char *str;
 244
 245         for (str = cp; *str == ' ' || *str == '\t'; str++)
 246                 ;
 247         *endp = str;
 248         return str != cp;
 249 }
 250
 251 static struct ctl_table cmm_table[];
 252
 253 static int cmm_pages_handler(ctl_table *ctl, int write, void __user *buffer,
 254                              size_t *lenp, loff_t *ppos)
 255 {
 256         char buf[16], *p;
 257         long nr;
 258         int len;
 259
 260         if (!*lenp || (*ppos && !write)) {
 261                 *lenp = 0;
 262                 return 0;
 263         }
 264
 265         if (write) {
 266                 len = *lenp;
 267                 if (copy_from_user(buf, buffer,
 268                                    len > sizeof(buf) ? sizeof(buf) : len))
 269                         return -EFAULT;
 270                 buf[sizeof(buf) - 1] = '\0';
 271                 cmm_skip_blanks(buf, &p);
 272                 nr = simple_strtoul(p, &p, 0);
 273                 if (ctl == &cmm_table[0])
 274                         cmm_set_pages(nr);
 275                 else
 276                         cmm_add_timed_pages(nr);
 277         } else {
 278                 if (ctl == &cmm_table[0])
 279                         nr = cmm_get_pages();
 280                 else
 281                         nr = cmm_get_timed_pages();
 282                 len = sprintf(buf, "%ld\n", nr);
 283                 if (len > *lenp)
 284                         len = *lenp;
 285                 if (copy_to_user(buffer, buf, len))
 286                         return -EFAULT;
 287         }
 288         *lenp = len;
 289         *ppos += len;
 290         return 0;
 291 }
 292
 293 static int cmm_timeout_handler(ctl_table *ctl, int write,  void __user *buffer,
 294                                size_t *lenp, loff_t *ppos)
 295 {
 296         char buf[64], *p;
 297         long nr, seconds;
 298         int len;
 299
 300         if (!*lenp || (*ppos && !write)) {
 301                 *lenp = 0;
 302                 return 0;
 303         }
 304
 305         if (write) {
 306                 len = *lenp;
 307                 if (copy_from_user(buf, buffer,
 308                                    len > sizeof(buf) ? sizeof(buf) : len))
 309                         return -EFAULT;
 310                 buf[sizeof(buf) - 1] = '\0';
 311                 cmm_skip_blanks(buf, &p);
 312                 nr = simple_strtoul(p, &p, 0);
 313                 cmm_skip_blanks(p, &p);
 314                 seconds = simple_strtoul(p, &p, 0);
 315                 cmm_set_timeout(nr, seconds);
 316         } else {
 317                 len = sprintf(buf, "%ld %ld\n",
 318                               cmm_timeout_pages, cmm_timeout_seconds);
 319                 if (len > *lenp)
 320                         len = *lenp;
 321                 if (copy_to_user(buffer, buf, len))
 322                         return -EFAULT;
 323         }
 324         *lenp = len;
 325         *ppos += len;
 326         return 0;
 327 }
 328
 329 static struct ctl_table cmm_table[] = {
 330         {
 331                 .procname       = "cmm_pages",
 332                 .mode           = 0644,
 333                 .proc_handler   = cmm_pages_handler,
 334         },
 335         {
 336                 .procname       = "cmm_timed_pages",
 337                 .mode           = 0644,
 338                 .proc_handler   = cmm_pages_handler,
 339         },
 340         {
 341                 .procname       = "cmm_timeout",
 342                 .mode           = 0644,
 343                 .proc_handler   = cmm_timeout_handler,
 344         },
 345         { }
 346 };
 347
 348 static struct ctl_table cmm_dir_table[] = {
 349         {
 350                 .procname       = "vm",
 351                 .maxlen         = 0,
 352                 .mode           = 0555,
 353                 .child          = cmm_table,
 354         },
 355         { }
 356 };
 357
 358 #ifdef CONFIG_CMM_IUCV
 359 #define SMSG_PREFIX "CMM"
 360 static void cmm_smsg_target(const char *from, char *msg)
 361 {
 362         long nr, seconds;
 363
 364         if (strlen(sender) > 0 && strcmp(from, sender) != 0)
 365                 return;
 366         if (!cmm_skip_blanks(msg + strlen(SMSG_PREFIX), &msg))
 367                 return;
 368         if (strncmp(msg, "SHRINK", 6) == 0) {
 369                 if (!cmm_skip_blanks(msg + 6, &msg))
 370                         return;
 371                 nr = simple_strtoul(msg, &msg, 0);
 372                 cmm_skip_blanks(msg, &msg);
 373                 if (*msg == '\0')
 374                         cmm_set_pages(nr);
 375         } else if (strncmp(msg, "RELEASE", 7) == 0) {
 376                 if (!cmm_skip_blanks(msg + 7, &msg))
 377                         return;
 378                 nr = simple_strtoul(msg, &msg, 0);
 379                 cmm_skip_blanks(msg, &msg);
 380                 if (*msg == '\0')
 381                         cmm_add_timed_pages(nr);
 382         } else if (strncmp(msg, "REUSE", 5) == 0) {
 383                 if (!cmm_skip_blanks(msg + 5, &msg))
 384                         return;
 385                 nr = simple_strtoul(msg, &msg, 0);
 386                 if (!cmm_skip_blanks(msg, &msg))
 387                         return;
 388                 seconds = simple_strtoul(msg, &msg, 0);
 389                 cmm_skip_blanks(msg, &msg);
 390                 if (*msg == '\0')
 391                         cmm_set_timeout(nr, seconds);
 392         }
 393 }
 394 #endif
 395
 396 static struct ctl_table_header *cmm_sysctl_header;
 397
 398 static int cmm_suspend(void)
 399 {
 400         cmm_suspended = 1;
 401         cmm_free_pages(cmm_pages, &cmm_pages, &cmm_page_list);
 402         cmm_free_pages(cmm_timed_pages, &cmm_timed_pages, &cmm_timed_page_list);
 403         return 0;
 404 }
 405
 406 static int cmm_resume(void)
 407 {
 408         cmm_suspended = 0;
 409         cmm_kick_thread();
 410         return 0;
 411 }
 412
 413 static int cmm_power_event(struct notifier_block *this,
 414                            unsigned long event, void *ptr)
 415 {
 416         switch (event) {
 417         case PM_POST_HIBERNATION:
 418                 return cmm_resume();
 419         case PM_HIBERNATION_PREPARE:
 420                 return cmm_suspend();
 421         default:
 422                 return NOTIFY_DONE;
 423         }
 424 }
 425
 426 static struct notifier_block cmm_power_notifier = {
 427         .notifier_call = cmm_power_event,
 428 };
 429
 430 static int cmm_init(void)
 431 {
 432         int rc = -ENOMEM;
 433
 434         cmm_sysctl_header = register_sysctl_table(cmm_dir_table);
 435         if (!cmm_sysctl_header)
 436                 goto out_sysctl;
 437 #ifdef CONFIG_CMM_IUCV
 438         rc = smsg_register_callback(SMSG_PREFIX, cmm_smsg_target);
 439         if (rc < 0)
 440                 goto out_smsg;
 441 #endif
 442         rc = register_oom_notifier(&cmm_oom_nb);
 443         if (rc < 0)
 444                 goto out_oom_notify;
 445         rc = register_pm_notifier(&cmm_power_notifier);
 446         if (rc)
 447                 goto out_pm;
 448         cmm_thread_ptr = kthread_run(cmm_thread, NULL, "cmmthread");
 449         rc = IS_ERR(cmm_thread_ptr) ? PTR_ERR(cmm_thread_ptr) : 0;
 450         if (rc)
 451                 goto out_kthread;
 452         return 0;
 453
 454 out_kthread:
 455         unregister_pm_notifier(&cmm_power_notifier);
 456 out_pm:
 457         unregister_oom_notifier(&cmm_oom_nb);
 458 out_oom_notify:
 459 #ifdef CONFIG_CMM_IUCV
 460         smsg_unregister_callback(SMSG_PREFIX, cmm_smsg_target);
 461 out_smsg:
 462 #endif
 463         unregister_sysctl_table(cmm_sysctl_header);
 464 out_sysctl:
 465         del_timer_sync(&cmm_timer);
 466         return rc;
 467 }
 468 module_init(cmm_init);
 469
 470 static void cmm_exit(void)
 471 {
 472         unregister_sysctl_table(cmm_sysctl_header);
 473 #ifdef CONFIG_CMM_IUCV
 474         smsg_unregister_callback(SMSG_PREFIX, cmm_smsg_target);
 475 #endif
 476         unregister_pm_notifier(&cmm_power_notifier);
 477         unregister_oom_notifier(&cmm_oom_nb);
 478         kthread_stop(cmm_thread_ptr);
 479         del_timer_sync(&cmm_timer);
 480         cmm_free_pages(cmm_pages, &cmm_pages, &cmm_page_list);
 481         cmm_free_pages(cmm_timed_pages, &cmm_timed_pages, &cmm_timed_page_list);
 482 }
 483 module_exit(cmm_exit);
 484
 485 MODULE_LICENSE("GPL");